Gear train



Sept. 1,1925.

c. A. P-ARsoNs ET'AL GEAR mun I Filed April 9, 1920 4 Sheets-Sheet l INVENTORS-- Char/c5 APar Stan/e $.CaoK, Lama Doug a litrys.

Sept. 1, 1925.

4 Shets-Sheet 2 INVENTORSz' GEAR TRAIN Filed April 9, 1920 c. A. PARSONS ET AL Charles/1 Parsmys,

Stan/e v Lou/s X4. M M W r Sept. 1, 1925.

C. A. PARSONS ET-AL GEAR TRAIN Filed April 9, 1920 4 Sheets-Sheet 5 Fig.8.

INVENTORS:

char/es A.Pa.rsons,

Stanley 8. Cook, Lou/s Mummy/a Sept. 1, 1925. 1,551,344

C. A. PARSONS ET AL GEAR'TRAIN Filed pril 9, 1920 4 Sheets-Sheet 4 Patented Sept- 1, 1925.

"STATES ASSIGNORS To SAID reasons.

PATENT OFFICE. 'cEARLEs ALGERNON. PARSONS, STANLEY SIMITH 0001:, AND tours mon'rntnn f DOUGLAS, or NEWCASTLE-ON-EEYNE, ENGLAND; SAID 0001: AND SAID DOUGLAS GEAR TRAIN;

Application flIedApril 9, 1920. Serial 1%. 372,612.

To all whom it may'concem: 1

- Be it known that we, .CHARLES ALGERNON PARSONS, STANLEY SMITH COOK, and Louis MORTIMER "DOUGLAS, all sub ects of the King The present invention relates 'to gear trains, especially; todouble-reduction gear trains whether of the single" helical,do'uble helical 'or spur'type, in which" each primary pinion ,driveswt'wm primary gear wheels mounted on intermediate shafts carrying secondary pinions which engage.

withthe-main gearv wheel-.1 KY 7 The ob'ectof the invention isto-provide.

for adjustment of the. gears so that the primary pinion transmits to the'two prim'ary;

sired'ratio: 5 1 7. Since each of apair of secondary. pinions engages withathe teeth ofithe Same secondary gear wheel and each-of the twoprimary wheels. forces-which arerequalor in a degear wheels has toiengagewith the teeth of the same; primary pinion, it is necessary, in

order to ensurethat the primary pinion is so inpropencontat with the teeth of, and drives equally through each intermediate shaft, to. have a veryexactyrelative circumferential dispositionpof the teeth of: the vae riousfinterengaging membersofjthe train,

and in. cases where double helical. teeth; are employed it is also necessary Ito have a similarly exact relative longitudinal disposition of the members.

It is found tobe practically impossible to cutthe' gears so accurately'that these conditions are realized and a further object of the invention is-to vobviatethis necessity of extreme accuracy in the cutting of the sets of teeth carried on the intermediate shafts of such a gear train in relation to each other.

The invention consists in'the particular combinations of elements, hereinafter described and particularly pointed out in the claims.

Referring to the gaccompanying draw- Figure 1 is an elevation showing dia-- grammatically an installation to which'the invention'is to be applied.

Figure 2 is a plan of the same. Figure 3 is a transverse section one of the intermediate shafts.

Figure 4 is an end view ofthe same." Figure 5 is an elevation, and

' through Figure 6 a plan of a modification'in which the bearings are slidably mounted.

Figures 7 and 8 are? enlargedsections at right angles showing the method ofmount? ing the bearings. 1 Figure!) shows a modification in which the primary gear wheels on the interme-f diate shafts are flexibly mounted. Figure 10 shows a detail ofthe mounting.

Figure 11 is an elevation of the modification shownin Figure-9. v I

Figure-12 isanend'view, and l a w 'wFigure 13 a transverse section of a form of the inventi'on in which both permanent and flexible adjustment is provided in the circumferential directionsl y In carrying the invention into'jefiectras illustrated in Figures 1 1. two 1 primary pinions it a are each arranged to drive two primary gear wheels 6 0 b a mounted oIi-intermediate shafts on which arejalso mounted secondary'pinions d e d e which engage with the secondary; gear wlleel f on the driven shaft 9; One 'of theprimary gear wheels is i-illustratedi in Figures 3' and 4 and comprises twoadjustable helices 1, 2,.bolted to webs 3, 4:, which are themselves bolted to a flange 5 on the intermediate shaft on 'which'are cut the secondarypinion teeth 6, 6. In this case thevgear train'is assembled by mounting all the members in position and the first or last member of the train is then looked Torque is then applied in the appropriate direction to the other members of the trainincludihg the two adjustable helices. The helices are constrained longitudinally but have circumferential freedom and they are each moved until each set of teeth is in pro er contact when they are bolted to the we and dowel pins or other registering means fitted to retain them permanently in this position.

According to a modification separate per-' manent adjustment of each separate helix is provided as in the preceding example but axial di- With a permanent adjustment as described above the major or first-degree inaccuracies of the gear train are provided for 'but ac-*:-

cording to the present invention, in order to provide for theminor or second-degree inaccuracies and thereby securecontinuously substantially equal power transmission throughthe two mtermedaate shafts, flex1- ble or resilient means are used in addition to the permanent adjustment above described.

In the form of such resilient means shown in Figures 5;to'8;the bearings 11 which carrythe 'prin'iary-pinion-' shafts 12 are slidably mounted so that they are capable of moving against the forces of retainingsprings 13 which are initially-compressed or extended. The motion th-us allowed to the axis of the pinion is in a direction non-parallel with the commontan'gent tothe faces of the-interengaging teetlrof the-primary gears and preferably in a direction substantially at right angles to these common tangents or at right angles -to'the plane containing the axes of'the two intermediate shafts. Dash-pots,

' or any other-known devices, may beprovided to damp out oscillations;

According" to another form of the resilient means, the drive is transmitted from each primary wheel to its shaft through spring devices such as are described in British patent specification No. 13019 of 1906:

This modification is shownin' Fignres 9, 10 and 11. Eachprimarywheel transmits force to-its'shaft with either directionbf rotation through springs 16,- which areinitially" free. One set of springs may be omitted however, so thatwhem going 'astern the force is transmitted non resil i ently from the" primary wheelsto' their shafts; The separate rims, 19 carrying the teeth, after setting the parts" as described above, are permanentlyjfi xed in position'by=means such as thepins, 25.

Inthe form of the "inventionshown" in Figures' 12' and 13, in addition to the flexible adjustment provided by the thin webs or spokes 18 carrying the two' helices 19, a permanent adjustment is provided "by bolting each of these helices in its correct circumferential position relatively to the rim 20 by means of bolts 21.. In this .case the wheel with the flexible spokes is keyed bykeys 22 to the intermediate shaft 24. In the examples illustrated the permanent adjustment has been made on the primary gear wheels beeause'ot the relatively small faces of these wheels and of the convenience of their dimensions tor adjustment; The adjustment can, however, be made on the secondary pinion.

Having now d-escribed our inventi'on', what we claim as new and desire twsecu-re by Letters Patent is 1. In combination *in a-gear train; a driving pinion" and a main driven" gear, and a plurality ofgeardrives between them, eaclr of said gear drives including a sha-ftcar'ry. ing'a set of pinions anda set'ot primary gears, the members'ot one of said sets beingrelat-itely' adjustable circumferentiallywith means for holdingthem relatively fixed in their adjusted position, whereby major inacs curacies may be" eliminated, and resilient means associated witlrtheigear' train whereby minor inaccuracies may' be automatically compensated for, the members of the gear setsbeingi non-flexible laterally, substantially as described.

2. In" combination in a gear 'train a' clriving pinion in right and left helical 'sections; a main! driven" gear in =ri-ght and leftheli'cal sections, and a plurality 0t gear 'drives be tween the pinion and driven 'gean'eachmade up ofa-primarygearin right'and'left helical sections-and *a' secondary pinionvin right and left helical sections; means for relatively adjusting the helicat sectionscircumferen tially' and setting them in a new fixed relation to eliminate majorfinaccuracies; and resilient means associated with the 'gear'train for compensating for minor inaccuracies," all of the sections being non-flexibledateral ly, substal iti-ally as'described'.

testimony' whereof we havesig'ne'd 'our names to this specification;

CHARLES nnennnon PARSGNS: STANLEY- oooiie LOUIS MORTIMER DOUGLAS; 

